This study will investigate the disposition of dapsone in vivo to characterize metabolism by alternative routes of metabolism. The objective is to determine the relative importance of each route of metabolism in the overall elimination of dapsone in humans. By using selective modulation of specific metabolizing enzymes by different agents, the enzymes that are involved in these reactions and their relative contributions to the formation of these metabolites will be evaluated. The study will be conducted in 50 normal healthy volunteers.